Ballmer was hired by Bill Gates at Microsoft in 1980, and subsequently left the MBA program at Stanford University.
In 2005, Microsoft sued Google for hiring one of its previous vice presidents, Kai-Fu Lee, claiming it was in violation of his one-year non-compete clause in his contract.
Microsoft's gross profit of 75 cents on every dollar in sales is double that of Google or IBM.
He followed this by announcing the company's purchase of Nokia 's mobile phone division in September 2013, his last major acquisition for Microsoft as CEO.
Ballmer served as director of Accenture Ltd. and a general partner of Accenture SCA from 2001 to 2006.